Electric guitar incorporating pickup means adapted to minimize beating effects



p 1,1964 c L. FENDER 3,147,332

ELECTRIC GUITARENCORPORATING PICKUP MEANS ADAPTED TO MINIMIZE BEATING EFFECTS 2 Sheets-Sheet 1 Filed Aug. 21, 1961 J1 ll llllll4 lll li I 27 24v AMP! was 25 m/vrzaz #54:

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United States Patent 3,147,332 ELECTRIC GUITAR INCORPORATING PICKUP MEANS ADAPTED T0 IVIENIMIZE BEATING EFFECTS Clarence L. Fender, 2212 E. Revere, Fullerton, Calif. Filed Aug. 21, 1961, Ser. No. 132,658 10 Claims. (Cl. 84-115) This invention relates to an electric guitar and pickup means therefor, including the combination of the guitar and the amplifier and loudspeaker means.

An object of the invention is to provide an electric guitar system in which there is a minimum of intermodulation or beating effects, so that the resulting sound is relatively free of distortion and is more musically satisfactory than in prior-art systems.

Another object is to provide an electric guitar system in which there is no overloading of the output tubes, or flapping of the loudspeaker means, due to the beats or pulses which occur in conventional electric guitars when FIGURE 1 is a fragmentary plan view illustrating a' Spanish guitar constructed in accordance with the present invention;

FIGURE 2 is an enlarged fragmentary plan view illustrating the portion of the guitar at which the pickup means are located;

FIGURE 3 is a transverse section taken on line 33 of FIGURE 2;

FIGURE 4 is a schematic wiring diagram of the electrical components of the system;

FIGURE 5 is a fragmentary perspective view illustrating a Hawaiian guitar constructed in accordance with a second embodiment of the invention;

FIGURE 6 is an enlarged fragmentary plan view illustrating the pickup of the Hawaiian guitar;

FIGURE 7 is a transverse section on line 77 of FIG- URE 6; and

FIGURE 8 is a schematicwiring diagram. 1

Referring to FIGURES 1-4 of the drawings, an electric guitar is indicated generally at 10 and comprises a body 11 having a neck 12 connected thereto. A plurality of strings, illustrated as six in number and numbered 13-18, are mounted over body 11 in tensioned relationship. The strings are generally parallel to each other and lie in a plane which is substantially parallel to the face of the body 11, such face being numbered 22. The strings are stretched between a bridge 23 and conventional tuning screws which are provided on a head (not shown) at the outer end of neck 12.

As in conventional guitars, the pitches of notes generated by the various strings 13-18 increase progressively from one edge of body 11 to the other. Thus, the string 13 adjacent one edge of the body is adapted to produce bass notes, whereas the string 18 adjacent the other edge is adapted to produce treble notes. The intermediate strings are adapted to produce intermediate notes having progressively-increasing pitches.

It frequently occurs that, because of the positions of the guitarists fingers on the neck 12, adjacent strings (such as 13-14, 16-17, etc.) will produce notes having substantially the same pitch. When this occurs in conventional guitars, the notes beat relative to each other to produce strong and undesirable pulsations in the associated amplifier and loudspeaker. These pulsations are extremely undesirable not only because they detract from the music generated by the instrument but also because they tend to overload the output tubes of the amplifier. They also cause excessive flapping of the loudspeaker.

To amplify upon the above, let it be assumed that the notes produced by adjacent strings, such as 13 and 14, are fifty cycles apart. The resulting beat note generated by both of the strings therefore has a frequency of fifty cycles per second. Because of the sympathetic vibration between the two strings, the amplitude or volume of the beat note (when at or near its peak) is on the order of twice the amplitude or volume of the note produced by either of the strings. The result is a very loud and undesirable sound, in comparison with the desired notes generated by the individual strings, which is not only bad from a musical standpoint but also produces the previously described adverse effects of overloading the output tubes, etc.

From the preceding paragraph it will be understood that such phrases as substantially the same pitch do not denote only pitches which differ by a few cycles, but also denote substantial pitch variationssuch as 50-100 cycles.

The above-indicated problem is solved by providing means whereby the notes produced by adjacent strings do not pass through-the same amplifier or loudspeaker, but only mix in the air. There is therefore no possibility that notes generated by adjacent strings will produce beating effects in the amplifier or loudspeaker means. This substantially eliminates the entire problem, since the pitches of notes generated by strings which are spaced from each other, that is to say are not adjacent, are normally so far apart that any beating effects are not severe.

In one illustrative form of the present invention, first and second pickups 24 and 25 are provided adjacent each other, such pickups being identical to each other and being offset transversely of the strings by a distance equal to the spacing between each two adjacent strings. The first pickup, numbered 24, is associated only with one set of alternate strings of the instrument, illustrated as Nos. 13, 15 and 17. The second pickup 25, on the other hand, is associated only with the remaining (even numbered) alternate strings.

The first pickup 24 is connected to a first amplifier 27 (FIGURE 4) and thus to a loudspeaker 28. The second pickup 25 is connected to a second amplifier 29 and thus to a loudspeaker 30.

It is to be understood that the invention may also be incorporated in systems in which there are more than two amplifiers and loudspeakers. For example, three pickups (and related amplifiers and loudspeakers) may be provided, each pickup being associated with each third string instead of each alternate string.

Each of the identical pickups 24 and 25 may comprise a plurality of elongated permanent-magnet pole pieces 31. The pole pieces are disposed in a plane which is perpendicular to the strings and also to the common plane of the strings, each pole piece being spaced from an associated string and being located directly therebeneath. Thus, in pickup 24 there is a pole piece directly beneath each of strings 13, 15 and 17, Whereas in pickup 25 there is a pole piece directly beneath each of strings 14, 16 and 18. Each pole piece is perpendicular to the common plane of the strings.

A coil of wire, numbered 32, is wound around the pole pieces 31 in each pickup. A suitable non-conductive casing 33 is mounted around the pickup and the coil in such manner as to leave exposed the pole-piece ends which are -13 adjacent the strings. Each casing is illustrated as being mounted in a corresponding recess 34 or 35 in body 11, being maintained in position by screws 36 which extend downwardly into the body. A mass 37 of a suitable resilient material, such as sponge rubber, is disposed between each casing and the bottom of the recess, so that adjustment of screws 36 will vary the distances between the pole pieces and the strings with which they are associated.

Summary of Operation, Embodiment of FIGURES 1-4 In the operation of the guitar and system shown in FIG-' URES 1-4, the guitarist adjusts the control means which are associated with the respective amplifiers 27 and 29, namely the tone and volume controls, so that they produce substantially equal responses. The attainment of equal responses is aided by the fact that the two pickups are disposed adjacent each other in a direction longitudinally of the strings, so that they sense the harmonics in substantially equal degree;

The guitar is then played in the normal manner, with the notes generated by vibration of the strings 13, 15 and 17 passing through amplifier 27, and the notes generated by vibration of strings 14, 16 and 18 passing through amplifier 29. Since notes generated by vibration of the odd-numbered strings are normally of substantially different pitch, no substantial pulsing occurs in the amplifier 27 or its loudspeaker 28 due to the above-described heating or intermodulation. correspondingly, since notes generated by vibration of the even-numbered strings are normally substantially different in pitch, there is no puls- 'ing produced in the amplifier 29 or its associated loudspeaker 30.

The notes generated by vibration of all strings mix in the air adjacent the two loudspeakers 28 and 30, it being understood that such loudspeakers are disposed adjacent each other and facing in the same direction so that the listener hears only one response. It is preferred that the amplifiers and loudspeakers be identical to each other.

Embodiment of FIGURES -8 There will next be described a pickup arrangement which is particularly adapted for guitars of the Hawaiian type, although it is also suitable for a Spanish guitar such as is shown in FIGURE 1. In Hawaiian guitars, the pickup is normally located close to the bridge, where the harmonics sensed by the pickup vary greatly in a direction longitudinally of the strings. This effect is much more pronounced in Hawaiian guitars than in Spanish guitars, since in Spanish guitars the pickup is normally spaced substantially farther from the bridge.

The Hawaiian guitar illustrated in FIGURE 5 has an elongated body 51 supported on legs which are fragmentarily indicated at 52. The tensioned strings 53-60 are mounted over body 51 in parallel relationship to each other, and in a plane which is substantially parallel to the body. The strings 53-60 are connected at one end of the body by a bridge 63. The electromagnetic pickup 64 is, as previously indicated, disposed closely adjacent the bridge 68, being constructed in the novel manner next to be described.

The pickup means 64 comprises an elongated nonconductive casing 66 which is mounted on a mass 67 of sponge rubber in a recess 68 adjacent bridge 63, the easing being adjustably secured in place by means of screws 69 which extend downwardly into the body. Mounted in casing 66 with their axes perpendicular to the common plane of strings 53-60 are a plurality of elongated permanent-magnet pole pieces 71-78, being illustrated as having cylindrical shapes.

The odd-numbered pole pieces 71, 73, 75 and 77 are respectively located directly beneath odd-numbered strings 53, 55, 57 and 59. Correspondingly, the even-numbered pole pieces 72, 74, 76 and 78 are respectively directly beneath the even numbered strings 54, 56, 58 and 60. The odd-numbered pole pieces lie along a first line per- &

apexes being associated with strings 53, 55, 57 and 59,

and the remaining corresponding apexes being associated with strings 54, 56, 58 and 60.

All of the eight pole pieces 71-78 have corresponding poles adjacent the plane of the strings, for example north poles. On the other hand, the coils 79-86 which are respectively associated with the pole pieces are reverse wound relative to each other as will next be described. Each coil is formed of many turns of fine insulated wire.

As shown in FIGURE 8, the coil 80 for string 54 is wound correspondingly to the coil 84 for string 58, whereas the coils 82 and 86 for strings 56 and 60 are each wound oppositely to the direction of winding of coils 80 and 84. Such coils 80, 82, 84 and 86 are connected in series-circuit relationship across the input of an amplifier and control means schematically represented at 87. The output of amplifier 87 is connected to a loudspeaker 88.

In similar manner, the coils 79 and 83 for strings 53 and 57 are wound correspondingly to each other, such manner of winding being opposite to the manner of winding of coils 81 and for strings 55 and 59. All four coils 79, 81, 83 and 85 are connected in series-circuit relationship to an amplifier and control means 89 associated with a loudspeaker 90.

Operation of the Embodiment of FIGURES 5-8 When a chord is struck on all eight of the strings, the

to be understood that the amplifiers and loudspeakers correspond to each other, the loudspeakers being adjacent and correspondingly directed. Since the pickup elements associated with adjacent strings generate signals which pass through different amplifiers to different loudspeakers, the beating effects are minimized or eliminated as described in detail relative to the first embodiment of the invention It is a feature of the present embodiment that the pole pieces associated with the even-numbered strings are olfset, longitudinally of the strings, only a very short distance relative to the pole pieces associated with the oddnumbered strings. Thus, all of the pole pieces sense substantially the same harmonics, despite the fact that the harmonics vary greatly with distance from the adjacent 7 appear in the sound wave emanating from the loudspeaker.

It is to be understood that the casing of the pickup may, if desired, be formed of electrically-conductive material. Furthermore, the pole pieces may be entirely covered by the casing.

It is also to be understood that, by making the various coils smaller in diameter, all of the pole pieces may be caused to lie along a single straight line instead of along two offset lines or along a zigzag line.

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

I claim:

1. An electrical musical instrument of the guitar class, which comprises a body, a plurality of strings mounted over said body in tensioned relationship, said strings being spaced and generally parallel relative to each other, said strings lying generally in a common plane, first pickup means operatively associated only with certain of said strings to sense the vibrations thereof and convert the same into electrical signals, second pickup means operatively associated only with other of said strings to sense the vibrations thereof and convert the same into electrical signals, a first amplifier and loudspeaker means operatively associated with said first pickup means, and a second amplifier and loudspeaker means operatively associated with said second pickup means, said certain of said strings including at least two strings separated from each other by at least one of said other of said strings, said other of said strings including at least two strings separated from each other by at least one of said certain of said strings.

2. The invention as claimed in claim 1, in which said first pickup means comprises an electromagnetic pickup mounted on said body and containing a plurality of permanent-magnet pole pieces which are respectively disposed beneath alternate ones of said strings, and in which said second pickup means comprises an electromagnetic pickup containing a plurality of permanent-magnet pole pieces which are respectively disposed beneath the remaining alternate ones of said strings.

3. The invention as claimed in claim 2, in which said pickups are disposed adjacent each other longitudinally of said strings.

4. The invention as claimed in claim 3, in which said pickups each include a single coil of Wire inductively associated with all of the pole pieces thereof and connected to the associated amplifier and loudspeaker means.

5. The invention as claimed in claim 3, in which said pickups each include a plurality of coils of wire respectively wound around the pole pieces thereof, said coils of wire being connected in series-circuit relationship relative to each other across the input of the associated amplifier and loudspeaker means.

6. The invention as claimed in claim 5, in which different ones of said coils of wire in each of said pickups are reverse-Wound relative to each other in order to effect cancellation of voltages induced therein from extraneous electromagnetic fields.

7. The invention as claimed in claim 1, in which said first pickup means comprises a plurality of permanentmagnet pole pieces respectively disposed beneath spaced ones of said strings, each of said pole pieces having Wound therearound an individual coil of wire, said coils of Wire being connected together in series-circuit relationship across the input of an associated amplifier and loudspeaker means, and in which said second pickup means comprises a plurality of permanent-magnet pole pieces respectively disposed beneath spaced ones of said strings, each of said pole pieces having wound therearound an individual coil of wire, said coils of wire being connected together in series-circuit relationship across the input of an associated amplifier and loudspeaker means.

8. The invention as claimed in claim 7, in which said first-mentioned pole pieces lie along a first line extending transverse to said strings, and in which said secondmentioned pole pieces lie along a second line extending transverse to said strings generally parallel to said first line, said second and first lines being spaced only a short distance from each other whereby all of said pole pieces lie along a zigzag path, said pole pieces being disposed sufficiently close together longitudinally of said strings to prevent substantial variation in the harmonics sensed thereby.

9. The invention as claimed in claim 7, in which said first-mentioned pole pieces lie along a first line extending transverse to said strings, and in which said second-mentioned pole pieces lie along a second line extending transverse to said strings generally parallel to said first line, said pole pieces being disposed sufficiently close together longitudinally of said strings to prevent substanital variation in the harmonics sensed thereby.

10. An electrical musical instrument of the guitar class, which comprises a body, a plurality of strings mounted over said body in tensioned relationship, said strings being spaced and generally parallel relative to each other, said strings lying generally in a common plane, first pickup means operatively associated only With certain of said strings to sense the vibrations thereof and convert the same into electrical signals, second pickup means operatively associated only with other of said strings to sense the vibrations thereof and convert the same into electrical signals, a first amplifier and loudspeaker means operatively associated with said first pickup means, and a second amplifier and loudspeaker means operatively associated with said second pickup means, said certain of said strings including only alternate ones of said strings, said other of said strings including only the remaining alternate ones of said strings.

References Cited in the file of this patent UNITED STATES PATENTS 2,596,258 Leslie May 13, 1952 2,784,631 Fender Mar. 12, 1957 2,817,261 Fender Dec. 24, 1957 2,887,000 Leslie May 19, 1959 2,896,491 Hover July 28, 1959 2,897,709 McCarty Aug. 4, 1959 2,899,644 Leslie Aug. 11, 1959 2,964,985 Webster Dec. 20, 1960 2,976,755 Fender Mar. 28, 1961 

1. AN ELECTRICAL MUSICAL INSTRUMENT OF THE GUITAR CLASS, WHICH COMPRISES A BODY, A PLURALITY OF STRINGS MOUNTED OVER SAID BODY IN TENSIONED RELATIONSHIP, SAID STRINGS BEING SPACED AND GENERALLY PARALLEL RELATIVE TO EACH OTHER, SAID STRINGS LYING GENERALLY IN A COMMON PLANE, FIRST PICKUP MEANS OPERATIVELY ASSOCIATED ONLY WITH CERTAIN OF SAID STRINGS TO SENSE THE VIBRATIONS THEREOF AND CONVERT THE SAME INTO ELECTRICAL SIGNALS, SECOND PICKUP MEANS OPERATIVELY ASSOCIATED ONLY WITH OTHER OF SAID STRINGS TO SENSE THE VIBRATIONS THEREOF AND CONVERT THE SAME INTO ELECTRICAL SIGNALS, A FIRST AMPLIFIER AND LOUDSPEAKER MEANS OPERATIVELY ASSOCIATED WITH SAID FIRST PICKUP MEANS, AND A SECOND AMPLIFIER AND LOUDSPEAKER MEANS OPERATIVELY ASSOCIATED WITH SAID SECOND PICKUP MEANS, SAID CERTAIN OF SAID STRINGS INCLUDING AT LEAST TWO STRINGS SEPARATED FROM EACH OTHER BY AT LEAST ONE OF SAID OTHER OF SAID STRINGS, SAID OTHER OF SAID STRINGS INCLUDING AT LEAST TWO STRINGS SEPARATED FROM EACH OTHER BY AT LEAST ONE OF SAID CERTAIN OF SAID STRINGS. 